Canister Stoves 101: Thread CareEver taken a good look at the threads on a canister?
Notice how they don't sharpen down to a "point" or line the way most threads do? These threads don't give your stove a lot to grip on to. Use them wrong, and you'll wear out your stove (literally).
I've assembled some basic tips for taking care of your stove's threads in Canister Stoves 101: Thread Care